CVE-2026-53255

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: validate advertising TLV before type checks

tlv_data_is_valid() reads each advertising data field length from

data[i], then inspects data[i + 1] for managed EIR types before

checking that the current field still fits inside the supplied buffer.

A malformed field whose length byte is the last byte of the buffer can

therefore make the parser read one byte past the advertising data.

KASAN reported the following when a malformed MGMT_OP_ADD_ADVERTISING

request reached that path:

BUG: KASAN: vmalloc-out-of-bounds in tlv_data_is_valid()

Read of size 1

Call trace:

tlv_data_is_valid()

add_advertising()

hci_mgmt_cmd()

hci_sock_sendmsg()

Move the existing element-length check before any type-octet inspection

so each non-empty element is proven to contain its type byte before the

parser looks at data[i + 1].